Natural gas, consisting primarily of methane, is an important fuel source. Natural gas also contains alkanes such as ethane, propane, butanes, and pentanes. Alkanes of increasing carbon number are normally present in decreasing amounts in crude natural gas. Carbon dioxide, nitrogen, and other gases may also be present. Most natural gas is situated in areas that are geographically remote from population and industrial centers. It is often difficult to utilize natural gas as an energy resource because of the costs and hazards associated with compression, transportation, and storage of natural gas.
Various efforts have been made to convert natural gas (primarily methane) to organic carbon compounds, including liquid hydrocarbons and simple alcohols such as methanol. For example, one method is a two-step conversion process. In the first step, methane is reformed with water vapor (also called steam reforming) to produce carbon monoxide and hydrogen (i.e., synthesis gas or “syngas”):CH4+H2O→CO+3H2 
In a second step, the produced syngas is converted to hydrocarbons. For instance, Sasol Ltd. of South Africa utilizes the Fischer-Tropsch process and utilizes both natural gas and coal feedstock to provide fuels that boil in the middle distillate range. Middle distillates may be defined as organic compounds that are produced between the kerosene and lubricating oil fractions in the refining processes. Middle distillates include light fuel oils and diesel fuel as well as hydrocarbon waxes.
It is also possible to convert natural gas to syngas via catalytic partial oxidation. In this process, natural gas is mixed with air, oxygen-enriched air, or oxygen, and introduced to a catalyst at elevated temperatures and pressures. The partial oxidation of methane yields a syngas mixture with a H2:CO molar ratio of 2:1, as shown below:CH4+½O2→CO+2H2 
The partial oxidation reaction is exothermic and requires the catalyst to be in the oxidative state, while the steam reforming reaction is strongly endothermic and requires the catalyst to be in a reduced state. Because the partial oxidation reaction is exothermic, it is difficult to control the reaction temperature in the catalyst bed. This is particularly true when scaling up the reaction from a micro reactor (e.g., ¼ in (about 6 mm) diameter reactor tube and less than 1 gram of catalyst) to a larger scale commercial reactor unit. This is because of the additional heat generated in large reactors relative to the limited heat transfer area available. If heat is not removed such that temperature control may be maintained, partial oxidation may transition to full oxidation, with the major quantity of end products being relatively low value carbon dioxide and water instead of syngas.
Conventional commercial means of converting methane into organic compounds involves first conversion to syngas followed by conversion to organic compounds via Fischer Tropsch process. This is often followed by cracking of the organic longer chain compounds to shorter chain compounds that may be used as a transportation fuel. There have been attempts to combine or eliminate one or more of these steps. U.S. Pat. No. 6,806,087 by Kibby et al. describes the use of two or more types of catalysts used simultaneously or in series for multi-step syntheses where optimum combination may be one that is the optimum for the first step or for the second step. United States Patent Application 2010/0307726 describes a Multi-Stage Multi-Tube Shell-and-Tube Reactor in an attempt to control different reactions within a single reactor. Other known technology utilizes complex reactor design in attempts to control various chemical reactions within a single reactor. United States Patent Application Publication 2003/0194362 by Rogers et al. discloses a multilayered porous ceramic chemical reactor. European Patent Application EP1584603A2 by Christensen et al. discloses a steam reforming reactor comprising a porous ceramic coated with catalyst. There are also various catalyst designs that have been disclosed that include porous designs in pellet and other geometric forms. U.S. Pat. No. 4,863,712 by Twigg, et al. discloses a catalyst comprising nickel and/or cobalt supported on shaped pieces of a silica-free ceramic foam having a network of irregular passages. There is still a need in the industry for a method of converting methane into high molecular weight organic compounds that is scalable with the ability to control temperatures in a less complex reactor design.
It is predicted that natural gas will outlast oil reserves by a significant margin and large quantities of natural gas are available in many areas worldwide. Therefore, there is continuing need and interest in developing methods, systems, and catalysts to convert natural gas to organic compounds in an economical fashion to better utilize this resource.